We can never be sure that the opinion we are endeavouring to stifle is a false opinion; and even if we were sure, stifling it would be an evil still.
All action is for the sake of some end; and rules of action, it seems natural to suppose, must take their whole character and color from the end to which they are subservient.
The only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others. His own good, either physical or moral, is not sufficient warrant.
Actions are right in proportion as they tend to promote happiness; wrong as they tend to produce the reverse of happiness. By happiness is intended pleasure and the absence of pain.
A party of order or stability, and a party of progress or reform, are both necessary elements of a healthy state of political life.
There are many truths of which the full meaning cannot be realized until personal experience has brought it home.